Centrifugal fan, air conditioner and control method of air conditioner

Abstract

The centrifugal fan comprises a volute, the volute is provided with a volute tongue, centrifugal fan blades are arranged in the volute, the volute is provided with an air inlet, the air inlet is formed in one axial side of the volute, the air inlet is provided with a backflow area, and in the rotating direction of the centrifugal fan blades, the centrifugal fan blades are arranged in the backflow area. The backflow area is located on the downstream of the volute tongue. The centrifugal fan is provided with a movable spoiler, and on the projection in the axial direction, the spoiler moves to only cover the backflow areas with different areas, so that the influence of backflow air generated by the centrifugal fan in the prior art on inlet air can be reduced, and the air outlet amount of the centrifugal fan is increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of centrifugal fan design, and particularly relates to a centrifugal fan, an air conditioner and a control method thereof. Background Art

[0002] When a centrifugal fan operates, the centrifugal impeller sucks air in the air inlet cavity into the volute, and then drives the air to rotate. Near the volute tongue, the high-pressure and high-speed air is discharged. Part of the air flows out of the volute outlet to the room, and the other part of the air remains in the fan. This part of the air forms a high-pressure area (recirculation area) near the volute tongue area of the centrifugal fan. The pressure in the high-pressure area is higher than the pressure in the air inlet cavity. At this time, the high-pressure air in the recirculation area will flow back to the air inlet cavity through the air inlet. Thus, it will hinder the air in the air inlet cavity from flowing into the volute, reducing the air circulation efficiency and the air volume.

[0003] In order to reduce the high-pressure air in the recirculation area from entering the air inlet cavity, a baffle is arranged between the recirculation area and the air inlet cavity to block the recirculating air from entering the air inlet cavity. However, the baffle of this scheme is fixedly arranged. When the rotational speed of the centrifugal fan of the centrifugal fan is relatively low, the area of the recirculation area is small, and the baffle blocks too much of the air inlet, reducing the air flow into the volute; when the rotational speed of the centrifugal fan of the centrifugal fan is relatively high, the area of the recirculation area is large, and the area of the air inlet blocked by the baffle is small, and the air in the recirculation area can still enter the air inlet cavity, affecting the air from entering the volute.

[0004] How to keep the air delivery volume of the centrifugal fan in different working states is a technical problem that needs to be solved urgently at present. Summary of the Invention

[0005] The present invention provides a centrifugal fan, an air conditioner and a control method thereof, which can reduce the influence of the recirculating air generated by the centrifugal fan in the prior art on the air inlet, and further improve the air outlet volume of the centrifugal fan.

[0006] In a first aspect, the present invention provides a centrifugal fan, including a volute, the volute having a volute tongue, a centrifugal impeller being arranged in the volute, the volute having an air inlet, the air inlet being arranged on one axial side of the volute, the air inlet having a recirculation area, and in the rotating direction of the centrifugal impeller, the recirculation area is located downstream of the volute tongue;

[0007] The centrifugal fan is provided with a movable baffle, and in the projection in the axial direction, the baffle can only cover different areas of the recirculation area when moving.

[0008] In some embodiments, at least one through hole extending along the axial direction is arranged on the baffle.

[0009] In some embodiments, along the direction in which air enters the volute from the air inlet, the flow area of the through hole gradually increases.

[0010] In some embodiments, one side of the baffle plate close to the center of the air inlet is the windward side, and the windward side is arc-shaped.

[0011] In some embodiments, the windward side is an elliptical side protruding towards the center of the air inlet.

[0012] In some embodiments, the centrifugal fan is provided with a receiving groove. The baffle plate can move closer to the center of the air inlet and move out of the receiving groove, and the baffle plate can move away from the center of the air inlet and at least partially enter the receiving groove.

[0013] In some embodiments, when there are through holes, there are multiple through holes. From one side close to the center of the air inlet to the opposite side, the multiple through holes are distributed gradually denser.

[0014] In some embodiments, one side of the baffle plate away from the center of the air inlet is the leeward side, and the shape of the leeward side is adapted to the edge of the air inlet.

[0015] In a second aspect, the present invention also provides an air conditioner including the centrifugal fan described above.

[0016] In a third aspect, the present invention also provides a control method for an air conditioner, which is used to control the air conditioner described above;

[0017] When the rotational speed of the centrifugal fan blade increases, control the baffle plate to move closer to the center of the centrifugal fan blade;

[0018] When the rotational speed of the centrifugal fan blade decreases, control the baffle plate to move away from the center of the centrifugal fan blade.

[0019] In this application, by providing a movable baffle plate at the air inlet, the position of the baffle plate at the air inlet can be adapted to the rotational speed of the centrifugal fan blade. The greater the rotational speed of the centrifugal fan blade, the larger the area of the air inlet covered by the baffle plate, and the smaller the rotational speed of the centrifugal fan blade, the smaller the area of the air inlet covered by the baffle plate. In this way, it is avoided that the high-pressure air in the recirculation area flows out through the air inlet and has an adverse effect on the air intake volume, and it is also avoided that the area of the air inlet covered by the baffle plate is too large and the air entering the volute from the air inlet is reduced, thereby improving the air intake volume and air delivery volume of the centrifugal fan. Description of the Drawings

[0020] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. The accompanying drawings in the following description are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0021] Figure 1 is the explosion diagram of the centrifugal fan according to an embodiment of the present invention;

[0022] Figure 2 is the external view schematic diagram of the centrifugal fan according to an embodiment of the present invention;

[0023] Figure 3 is the schematic diagram when the guide ring of the centrifugal fan according to an embodiment of the present invention is provided with a receiving groove;

[0024] Figure 4 is the schematic diagram of the recirculation area generated when air flows in the volute according to an embodiment of the present invention;

[0025] Figure 5 is the schematic diagram when the baffle plate and the swing arm are combined together according to an embodiment of the present invention;

[0026] Figure 6 is the schematic diagram when the baffle plate moves into the receiving groove according to an embodiment of the present invention;

[0027] Figure 7 is the schematic diagram when the baffle plate moves out of the receiving groove according to an embodiment of the present invention;

[0028] Figure 8 is the schematic diagram when the windward edge of the baffle plate is aligned with the edge of the air inlet according to an embodiment of the present invention;

[0029] Figure 9 is the axial schematic diagram when the baffle plate moves out of the receiving groove according to an embodiment of the present invention;

[0030] Figure 10 is the axial schematic diagram when the baffle plate partially enters the receiving groove according to an embodiment of the present invention;

[0031] Figure 11 is the schematic diagram when the baffle plate covers a smaller area of the air inlet according to an embodiment of the present invention;

[0032] Figure 12 is in the embodiment of the present invention Figure 11 is the schematic diagram when the baffle plate covers a larger area of the air inlet on the basis of;

[0033] Figure 13 is in the embodiment of the present invention Figure 12 is the schematic diagram when the baffle plate covers an even larger area of the air inlet on the basis of;

[0034] Figure 14 is a data table of the simulation experiment of the centrifugal fan according to the embodiment of the present invention;

[0035] Figure 15 is a schematic diagram of the turbulent kinetic energy distribution when the air flowing back enters the air inlet chamber when the baffle is provided in the embodiment of the present invention and the rotational speed of the wind blade is 2300 rpm;

[0036] Figure 16 is a schematic diagram of the turbulent kinetic energy distribution when the air flowing back enters the air inlet chamber when no baffle is provided in the prior art and the rotational speed of the wind blade is 2300 rpm.

[0037] The reference numerals are:

[0038] 1, volute; 2, volute tongue; 3, centrifugal wind blade; 4, baffle; 5, swing arm; 6, guide ring; 7, receiving groove; 8, HEPA net bracket; 9, cover plate; 10, air inlet; 101, recirculation zone; 401, through hole. Detailed Embodiment

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way restrictive of the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] In the description of the present invention, it should be understood that the orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" and the like usually indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, so it cannot be understood as a limitation on the protection scope of the present invention; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0041] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper", etc. may be used herein to describe the spatial positional relationship of a device or feature shown in the figures with respect to other devices or features. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures will then be oriented "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both orientations of "above" and "below". The device may also be oriented in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations will be made for the spatial relative descriptions used herein.

[0042] In addition, it should be noted that the use of terms such as "first", "second", etc. to define components is only for the convenience of differentiating the corresponding components. Without further statement, the above terms have no special meaning, and thus should not be construed as limiting the protection scope of the present invention.

[0043] Referring jointly to Figure 1-13 As shown, the centrifugal fan includes a volute 1, the volute 1 has a volute tongue 2, a centrifugal impeller 3 is disposed in the volute 1, the volute 1 has an air inlet 10, the air inlet 10 is disposed on one axial side of the volute 1, the air inlet 10 has a recirculation zone 101, and in the direction of rotation of the centrifugal impeller 3, the recirculation zone 101 is located downstream of the volute tongue 2;

[0044] The centrifugal fan is provided with a movable baffle 4, and in the projection in the axial direction, the movement of the baffle 4 can only cover different areas of the recirculation zone 101.

[0045] One side of the air inlet 10 is the inner cavity of the volute 1, and the centrifugal impeller 3 rotates in the inner cavity of the volute 1. The axial direction in this application refers to the axial direction of the volute 1 and also the axial direction of the centrifugal impeller 3.

[0046] As Figure 4As shown, in the direction of rotation of the centrifugal fan blade 3, the rotation of the centrifugal fan blade 3 causes air to enter the volute 1 from the air inlet 10 and perform a centrifugal motion driven by the centrifugal fan blade 3, and then flow out from the moving volute tongue 2. Since the air cannot completely flow out from the volute tongue 2 when flowing through the connection between the volute tongue 2 and the volute 1, a small part of the air flows to the downstream of the volute tongue 2. As shown in the figure, the area of the downstream of the volute tongue 2 where this part of the air flows is the recirculation area 101. It should be emphasized that the recirculation area 101 is not an area with a fixed size. The greater the rotation speed of the centrifugal fan blade 3, the larger the projected area of the recirculation area 101 in the direction of the air inlet 10, and the smaller the rotation speed of the centrifugal fan blade 3, the smaller the projected area of the recirculation area 101 in the direction of the air inlet 10. The pressure in the recirculation area 101 is relatively high, and air can flow out from the air inlet 10. By setting the baffle 4, the air in the recirculation area 101 can basically not flow out from the air inlet 10 to the outside of the volute 1. In this way, the blockage of the incoming air by the recirculated air is reduced, and the air intake volume entering from the air inlet 10 is increased (considering the viscosity of the air, when the air flows out from the air inlet 10 to the outside of the volute 1, the speed of the air entering the volute 1 will be reduced. By setting the baffle 4 to block part of the air inlet 10, although the area of the air inlet 10 is reduced, the impact on the air intake speed is relatively small. Compared with not setting the baffle 4, setting the baffle 4 can increase the air intake volume), and thus the air output volume of the centrifugal fan is increased.

[0047] Since in the projection in the axial direction, the movement of the baffle 4 can only cover different areas of the recirculation area 101 (the "only" here emphasizes that the baffle 4 only covers the recirculation area 101 and does not cover the gas area, and the baffle 4 does not affect the normal entry of air into the volute 1. That is, in the axial direction, no matter how the baffle 4 moves, it will not cover other areas of the air inlet 10 except the recirculation area 101), this makes it that when the rotation speed of the centrifugal fan blade 3 is relatively small, the projected area of the recirculation area 101 in the axial direction is also relatively small. Move the baffle 4 to make the baffle 4 cover a smaller area of the recirculation area 101 to avoid the baffle 4 covering too large an area and hindering the normal air intake (external air enters the volute 1 from the air inlet 10), thereby increasing the air intake volume entering the volute 1 and increasing the air output volume of the centrifugal fan. Correspondingly, when the rotation speed of the centrifugal fan blade 3 is relatively large, the projected area of the recirculation area 101 in the axial direction is also relatively large. Move the baffle 4 to make the baffle 4 cover a larger area of the recirculation area 101 to avoid the baffle 4 covering too small an area and the baffle 4 being unable to effectively block the high-pressure air in the recirculation area 101, resulting in the air in the recirculation area 101 flowing out from the air inlet 10 and hindering the external air from entering the volute 1 from the air inlet 10; thereby increasing the air intake volume entering the volute 1 and increasing the air output volume of the centrifugal fan.

[0048] The centrifugal fan is also provided with a cover plate 9 and a HEPA mesh bracket 8.

[0049] Preferably, as Figure 4 andFigure 5 As shown, at least one through hole 401 extending along the axial direction is provided on the baffle 4.

[0050] The through hole 401 is provided on the baffle 4, and the high-pressure air in the return flow area 101 flows out from the through hole 401, which can quickly and effectively reduce the pressure in the return flow area 101. When the air in the return flow area 101 flows out of the volute 1 from the through hole 401, the through hole 401 has a damping effect on the air, reducing the outflow speed of the air, thereby weakening the return effect and effectively increasing the air volume entering the volute 1. A part of the high-pressure air in the return flow area 101 flowing out from the through hole 401 can also reduce the eddy current condition in the return flow area 101, enabling the air to rotate better in the volute 1 driven by the centrifugal impeller 3, improving the air output and the air output speed.

[0051] Preferably, along the direction of air entering the volute 1 from the air inlet 10, the flow area of the through hole 401 gradually increases.

[0052] Along the direction of air entering the volute 1 from the air inlet 10, the flow area of the through hole 401 gradually increases, that is, the through hole 401 forms a flared structure with the flare facing the inside of the volute 1. In this way, when the high-pressure air in the return flow area 101 flows along the flared through hole 401, since the flow area of the through hole 401 gradually decreases, when the air flows in the through hole 401, the air reflects in the through hole 401, thereby reducing the speed of the air flowing out of the through hole 401. Correspondingly, since the flare faces the inside of the volute 1, the amount of air outside the volute 1 entering the volute 1 through the through hole 401 is extremely small, and basically no convection is formed in the through hole 401, which is beneficial to the air in the return flow area 101 flowing outwards through the through hole 401. In addition, when the sound in the volute 1 diffuses outwards along the through hole 401, the sound can also be reflected in the flare. Since the flare faces the inside of the volute 1, the flow direction of the sound after reflection is generally towards the inside of the volute 1, which is beneficial to reducing the propagation of noise.

[0053] Preferably, as Figure 4 、 Figures 7 to 13 shown, the side of the baffle 4 close to the center of the air inlet 10 is the windward side, and the windward side is arc-shaped.

[0054] When the external air enters the volute 1, it will pass through the windward side. Setting the windward side as arc-shaped is beneficial to reducing the friction between the air and the baffle 4 and reducing the friction noise. It is also beneficial to reducing the acting force between the air entering the volute 1 and the baffle 4, reducing the vibration of the baffle 4, and improving the stability of the movement of the baffle 4.

[0055] Preferably, as Figure 4 、 Figures 7 to 13 shown, the windward side is an elliptical side protruding towards the center of the air inlet 10.

[0056] By making the windward edge a convex elliptical edge, the windward edge of the baffle 4 is made more consistent with the outer edge of the recirculation area 101, reducing the impact of the baffle 4 on the incoming air.

[0057] Preferably, as Figure 3 , Figure 6 , Figure 9 and Figure 10 shown, the centrifugal fan is provided with a receiving groove 7, and the baffle 4 can move closer to the center of the air inlet 10 and move out of the receiving groove 7, and the baffle 4 can move away from the center of the air inlet 10 and at least partially enter the receiving groove 7.

[0058] By providing the receiving groove 7, the baffle 4 can enter the receiving groove 7 to avoid the baffle 4 being affected by the external air flow and causing vibration and noise. During the movement of the baffle 4 towards the air inlet 10, part of the baffle 4 is located in the receiving groove 7, and the receiving groove 7 has an axial limiting function on the baffle 4, avoiding or reducing the possibility of the baffle 4 vibrating and generating noise due to different pressures on both sides of the baffle 4.

[0059] Furthermore, as Figure 1 and Figure 3 , Figure 14 shown, a guide ring 6 is provided around the air inlet 10. The inside of the guide ring 6 is an air inlet cavity. The external air first enters the air inlet cavity under the action of the centrifugal fan blades 3, and then enters the volute 1 through the air inlet 10. When the centrifugal fan blades 3 rotate, part of the air cannot flow out from the volute tongue 2, but enters the volute 1 downstream of the volute tongue 2 (with the rotation direction of the centrifugal fan blades 3 as a reference), and then forms a high pressure in the area near the volute tongue 2 (recirculation area 101) in the volute 1. The high pressure in the recirculation area 101 is higher than the pressure in the air inlet cavity of the centrifugal fan, which causes the high-pressure air in the recirculation area 101 to flow out (recirculate) from the air inlet 10 of the centrifugal fan to the air inlet cavity. In the air inlet cavity, the recirculated air will hit the corner of the air inlet cavity to form eddy currents and generate noise; at the same time, the recirculated air also collides with the air entering the air inlet cavity from the outside to generate noise; when the recirculated air collides with the air entering the air inlet cavity from the outside, it also reduces the flow rate of the air flowing from the air inlet cavity into the volute 1, thereby reducing the air volume. By providing the baffle 4 with through holes 401, the air in the recirculation area 101 enters the air inlet cavity through the through holes 401, that is, the through holes 401 can weaken the pressure of the air in the recirculation area 101, reduce the turbulent noise in the recirculation area 101, and increase the air inlet efficiency. The air flowing into the air inlet cavity through the through holes 401 has a lower flow rate, a lower impact intensity on the side wall of the air inlet cavity, and less interference with the air in the air inlet cavity, which is beneficial for the air in the air inlet cavity to enter the volute 1.

[0060] The simulation test shows that referring to the one provided with the baffle 4Figure 14 and without the baffle plate Figure 15 and the simulation result table at different rotational speeds of the wind blade( Figure 13 , Figure 13 The efficiency in it refers to the ratio of the total pressure power of the centrifugal fan to the shaft power. The total pressure power refers to the power consumed by the fan to do work on the gas per unit time, and the shaft power of the centrifugal fan refers to the power required to drive the rotation of the fan shaft). When the rotational speed of the centrifugal wind blade is 2300 rpm (revolutions per minute), Figure 14 in it, the peak value of the turbulent kinetic energy generated when the air in the recirculation zone 101 enters the air inlet cavity through the through hole 401 is 33.4, Figure 15 the peak value of the turbulence generated when the air in the recirculation zone in it flows out from the air inlet hole to the air inlet cavity is 46.2. In the fluid field, the greater the turbulent kinetic energy, the higher the degree of flow chaos, and the greater the noise generated by the fluid hitting the entity; correspondingly, the smaller the turbulent kinetic energy, the lower the degree of flow chaos, and the smaller the noise generated by the fluid hitting the entity. That is to say, when the rotational speed of the wind blade is the same, the centrifugal fan of the present application provided with a baffle plate generates less noise.

[0061] Furthermore, the receiving groove 7 is arranged on the side wall of the guide ring 6.

[0062] Preferably, as Figure 4 , Figures 7 to 13 shown, when the through hole 401 is provided, there are a plurality of the through holes 401, and from one side close to the center of the air inlet 10 to the opposite side, the plurality of the through holes 401 are distributed gradually densely.

[0063] When the rotational speed of the centrifugal impeller 3 is relatively low, the area of the baffle 4 located in the receiving groove 7 is relatively large, and the area of the air inlet 10 covered is relatively small; when the rotational speed of the centrifugal impeller 3 is relatively high, the area of the baffle 4 located in the receiving groove 7 is relatively small, and the area of the air inlet 10 covered is relatively large; that is, the greater the rotational speed of the centrifugal impeller 3, the larger the area of the baffle 4 covering the air inlet 10, and the smaller the rotational speed of the centrifugal impeller 3, the smaller the area of the baffle 4 covering the air inlet 10. Through "the baffle 4 can move closer to or away from the center of the air inlet 10; there are multiple through holes 401, and from the side close to the center of the air inlet 10 to the opposite side, the multiple through holes 401 are distributed gradually denser", this makes it that the greater the rotational speed of the centrifugal impeller 3, the larger the area of the baffle 4 covering the air inlet 10, and at the same time, the through holes 401 on the baffle 4 covering the part of the air inlet 10 are also denser. The denser through holes 401 are beneficial to decelerating and reducing the noise of the air in the recirculation area 101 with a relatively large pressure. When the rotational speed of the centrifugal impeller 3 is relatively low, the air flow rate in the volute tongue is relatively low, and the pressure in the recirculation area and the projected area of the recirculation area in the axial direction are also relatively small, and there is no need for a baffle with a relatively large area to block. Moreover, the rotational speed of the centrifugal fan is relatively low, and the through holes 401 are relatively dense, and the air flow rate flowing out of the through holes 401 is excessive. The air in this part colliding with the solid part in the air inlet cavity will generate relatively large noise and affect the air in the air inlet cavity from entering the volute 1.

[0064] Preferably, as Figure 7 shown, the side of the baffle 4 away from the center of the air inlet 10 is the leeward side, and the shape of the leeward side is adapted to the edge of the air inlet 10.

[0065] The shape of the leeward side is adapted to the periphery of the air inlet 10, which makes it that when the baffle 4 is completely removed from the receiving groove 7, the leeward side of the baffle 4 and the edge of the air inlet 10 can be matched to form a seal, avoiding or reducing the air in the recirculation area 101 from flowing out from the baffle 4 and the edge of the air inlet 10.

[0066] Preferably, as Figure 5 、 Figures 11 to 13 shown, a swing arm 5 is arranged on the baffle 4, the fixed end of the swing arm 5 is fixed together with the baffle 4, and the rotating end of the swing arm 5 is hinged on the guide ring 6.

[0067] By swinging the swing arm 5, the movement of the baffle 4 is driven, and the setting is convenient.

[0068] Further, a motor is arranged at the hinge end, and the swing arm 5 is driven to swing by the motor. Further, the motor is a servo motor, and the servo motor is fixed on the guide ring 6 by bolts.

[0069] The present invention also provides an air conditioner, including the centrifugal fan described above.

[0070] The air conditioner is provided with a fresh air module, and the centrifugal fan is the fan of the fresh air module. The operation of the centrifugal fan is beneficial to increasing the air volume of the fresh air.

[0071] Furthermore, the air conditioner can be a fresh air device.

[0072] The present invention also provides a control method for an air conditioner, which is used to control the above-mentioned air conditioner;

[0073] When the rotation speed of the centrifugal impeller 3 increases, control the baffle 4 to move closer to the center of the centrifugal impeller 3;

[0074] When the rotation speed of the centrifugal impeller 3 decreases, control the baffle 4 to move away from the center of the centrifugal impeller (3);

[0075] That is to say, the area of the inlet 10 covered by the baffle 4 is proportional to the rotation speed of the centrifugal impeller 3.

[0076] Furthermore, for the convenience of control, the moving position of the baffle 4 can be set at three positions. For example, when the rotation speed of the centrifugal impeller 3 is relatively low and in the first rotation speed range, the baffle 4 covers a smaller part of the inlet 10. At this time, taking the position of the swing arm 5 as a reference, the swing arm 5 swings the first angle (equivalent to the swing angle of the swing arm 5 being 0°). When the rotation speed of the centrifugal impeller 3 increases and is in the second rotation speed range, the swing arm 5 swings to make the baffle 4 cover a larger area of the inlet 10. At this time, the swing arm 5 swings the second angle (for example, swings 7.5°). Similarly, when the rotation speed of the centrifugal impeller 3 reaches the third rotation speed range, the swing arm 5 swings a larger angle to make the baffle 4 cover a larger area of the inlet 10. At this time, the swing arm 5 swings the third angle (for example, swings 15°).

[0077] It is easy for those skilled in the art to understand that, on the premise of no conflict, the advantageous technical features of the above-mentioned various methods can be freely combined and superimposed.

[0078] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A centrifugal fan, comprising a volute (1), the volute (1) having a volute tongue (2), a centrifugal impeller (3) being disposed within the volute (1), the volute (1) having an air inlet (10), the air inlet (10) being disposed on one axial side of the volute (1), characterized in that, The air inlet (10) has a reflux area (101), and in the rotating direction of the centrifugal fan blade (3), the reflux area (101) is located downstream of the volute tongue (2). The centrifugal fan is provided with a movable baffle (4), and in the projection in the axial direction, the movement of the baffle (4) can only cover different areas of the reflux area (101).

2. The centrifugal fan according to claim 1, wherein At least one through hole (401) extending along the axial direction is provided on the baffle (4).

3. The centrifugal fan according to claim 2, wherein, Along the direction of air entering the volute (1) from the air inlet (10), the flow area of the through hole (401) gradually increases.

4. The centrifugal fan according to claim 1, wherein One side of the baffle (4) close to the center of the air inlet (10) is the windward side, and the windward side is arc-shaped.

5. The centrifugal fan according to claim 4, characterized in that, The windward side is an elliptical side protruding towards the center of the air inlet (10).

6. The centrifugal fan according to any one of claims 1-5, characterized in that, The centrifugal fan is provided with a receiving groove (7), and the baffle (4) can move close to the center of the air inlet (10) and move out of the receiving groove (7), and the baffle (4) can move away from the center of the air inlet (10) and at least partially enter the receiving groove (7).

7. The centrifugal fan according to claim 6, wherein When there are through holes (401), there are multiple through holes (401), and from one side close to the center of the air inlet (10) to the opposite side, the multiple through holes (401) are distributed gradually denser.

8. The centrifugal fan according to claim 4, characterized in that, One side of the baffle (4) away from the center of the air inlet (10) is the leeward side, and the shape of the leeward side is adapted to the edge of the air inlet (10).

9. An air conditioner, characterized in that, Including the centrifugal fan according to any one of claims 1-8.

10. A control method for an air conditioner, characterized in that, For controlling the air conditioner according to claim 9; When the rotational speed of the centrifugal fan blade (3) increases, control the baffle (4) to move close to the center of the centrifugal fan blade (3); When the rotational speed of the centrifugal fan blade (3) decreases, control the baffle (4) to move away from the center of the centrifugal fan blade (3).

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